From its northwest corner to its southeast coast, the world's biggest island has a band of relatively warm bedrock.
Scientists say this confirms Greenland ran over a hotspot of upwelling molten rock tens of millions of years ago as it shifted towards the Arctic.
It's like the underside of the island got a good roasting in the distant past and still has the big scar to prove it.
That hotspot, by the way, is the one which today is building Iceland in the middle of the North Atlantic.
The plume of broiling rock rising from deep inside the Earth has broken through the thin ocean floor at Iceland's location and is now creating new land with regular eruptions of lava.
Geothermal heat flux reveals the Iceland hotspot track underneath Greenland, by Yasmina M. Martos; Tom A. Jordan; Manuel Catalan; Thomas M. Jordan; Jonathan L. Bamber; David G. Vaughan. Geophysical Research Letters. First published: 01 August 2018 https://doi.org/10.1029/2018GL078289